They are characins from what i have read. i have two 8 inchers with my payara and my redtail cuda and now with a stripe pike or Boulengrerell.
Honestly these are very cheap and very hardy fish that eat like savages even though they dont have teeth. i had major doubts when i bought these fish as to how "predatory" they would be and they are way cool. i love the pair that i have.
very cool fish to have, and they are certainly not skittish or lame. no chance. they do get a little over protective of their territory sometimes. they even attack my redtail from time to time but they dont have any teeth to do damage.
awesome fish and certainly not a waste of time. coolest top water predator hands down for a small tank like a 55 in my opinion. just keep in mind that full grown they are like 10 inches and they jump like a mother so keep a lid on. hujeta is the only fish ive lost to the floor so far.